ST25DV16K I2C RFID EEPROM Breakout - STEMMA QT / Qwiic

This RFID tag is really unique: it works with mobile phones just like other RFID tags, but you can reprogram it over I2C. The tag shows up as an ISO/IEC 15693 (13.56MHz) chip which is readable by phones and tablets. This could be interesting in situations where you want a  tag that can be re-written dynamically when connected to a controller. For example, we did a test where we had a microcontroller write different URLs a few seconds apart, and the mobile phone detected the different URLs one after the other.

Note that the most popular hobby RFID reader/writer chips like the PN532 do not support ISO15693 so you cannot use those to read the ST25DV tag once programmed! We used both Apple and Android phones with success to read the tags.